GCM 2222- Intro to Packaging Production Quiz 4

Caliper Variation

The random difference of thickness, within a given minimum and maximum range, for film, paper, and/or board types of products.

Enclosed Doctor Blade

An enclosed chamber containing a doctor blade at the top and bottom with seals on each end. Ink is pumped into the chamber, and a drain is provided to recirculate the excess ink back to the pump. The unit mounts directly to the anilox roll to replace the meter roll and can be used in either forward or reverse rota on print stations. Ink containment is usually a benefit with enclosed doctor blades because ink slinging is eliminated. As with the other doctor blade systems, this unit uses the same type of blades, and the blades must be changed with every job.

Engraving

To cut or etch an image into a hard surface by using a mechanical tool, chemicals, or a laser

Extensible Films

A plastic material that can stretch easily and is used in the flexible packaging market.

Gear Marking

Defects in flexographic printing that appear as lateral stripes or varying tone and most prominently noticed in vignettes. These defects sometimes appear at uniformly spaced distances corresponding to the distance between gear teeth. They are known to be caused by errors in gear tooth profile and pitch variation; however, any cause of transmission error between anilox roll, plate roll, and web can produce gear marking.

Heat Resistance

The ability of a material to withstand heat.

Highlight Area

Lighter printing parts of a halftone reproduction.

Hue

The characteristics that identify a color, such as red, yellow, green, etc.

Ink Fountain

A stainless steel, formed plastic, or cardboard tray that is installed into the print station to allow the meter roll to rest in the ink and transfer ink to the anilox roll. An ink fountain is used in flexographic and UV flexographic printing except when replaced with an enclosed doctor blade.

Laminating

When a second web, usually a clear film, is laminated to the original web. Laminating is typically used to provide a protective cover over the printed image. The most common method is to apply an adhesive coating to the web and then laminate the second material onto it. Another method is to use a pressure-sensitive laminate with a protective liner that requires no adhesive application but does require the liner to be removed as waste.

Meter Roll

Also known as doctor roll or fountain roll. In a typical flexographic or UV flexographic press, the meter roll is a rubber- or compound-covered roll. The meter roll rests in the ink and is brought into contact with the anilox roll with enough pressure to meter excess ink from the surface of the anilox roll. When a reverse angle doctor blade is used, the meter roll is brought close to the anilox roll without touching it to provide a heavy film of ink that is then scraped off with the doctor blade.

Line Work

Any printed copy that is made up of lines, such as type, UPC (Universal Product Code) symbols, or pen and ink drawings.

Perforating

A row or series of cuts in the web that leaves small uncut sec ons between the cuts to keep the material in a con nuous piece yet allow the material to be easily separated by tearing the uncut sec ons. This opera on can be performed in the longitudinal or lateral direction of the web.

Picking

The condition that occurs when the ink has not completely cured or dried on the web find adheres to a rolling element in the press, usually a nip roll or idler roll. This condition appears in the form of small areas of ink that are removed by the contact with _the rolling elements and reveals the web or previously printed color below. This condition can also occur when a roll that contacts the printed side of the web has an excessively rough surface finish even if the ink has sufficient cure.

Registry (Linear and Lateral)

In a web- fed press, work is performed to the web in various stations along the length of the press. The work performed can be printing, diecuttng, hole punching, perforating, creasing, etc. The degree of alignment in which that work is performed in a given station relative to all other stations is known as registry or register. Registry accuracy is measured from repeat to repeat to determine the range of registry e1Tor as well as a frequency or any pattern that may develop. Lineal registry, also known as rotational or longitudinal registry, is registry in the direction of the web path, Lateral registry, also known as side registry, is registry across the width of the web.

Repeat Increments

The pitch of the gears used to drive the tooling. All gears have a circular pitch. the distance from one tooth to the next when measured along the pitch line: The industry standard in narrow web printing is 1/8 circular pitch (CP) gearing. This means that any job run must have a length divisible by 1/8 inch (3.18 mm). Other seldom used gearing standards are 1/16 CP and 32 diametral pitcl1 (DP). Diametral pitch must be converted to circular pitch in- order to determine the repeat increment. The 32 DP gear is 0.0982 CP while' the 1/ 16 CP will provide increments of 1/16 inch (1.59 mm). With the development of servo drives, it is now possible to have infinitely variable repeat lengths without being as concerned with gear pitch.

Servomotor

Motors equipped with a specially- developed motor feedback for position and speed determination.

Screen Ruling

The number of rows of dots per inch used to reproduce a halftone or tinted area.

Top Side Diecutting

When the die whether flat or rotary is positioned to cut the top or front side of the web.

Trapping/Wet Trapping

The process in which the boundaries of one printed image are increased relative to a second image so that the boundaries overlap. This creates a tolerance for registration error. Dry trapping is the process used in flexographic printing where the first color printed must be dried or cured before the second color is printed. Wet trapping allows multiple colors to be printed on top of each other without drying or curing, relying instead on ink chemistry. Trapping also refers to overprinting one color over another, e.g., blue over yellow to get green or any color over opaque white on a clear film.